The minimum prevalence of gluten sensitivity among the general population of northern and southern Iran is 1:104. The best screening test for the detection of GSE in the general population is IgA tTG-Ab.

3240 The role of pulmonary hypertension as a common and attributable cause of mortality in patients with sickle cell disease remains controversial. To assess this question and explore risk factors for death in patients with sickle cell disease we evaluated 632 patients in the Walk-PHASST pulmonary hypertension screening cohort, recruited from nine different study sites in the United States and one site in the United Kingdom. Methods: Patient characteristics and their associations with mortality were analyzed with Cox proportional hazards regression analysis. Based on data from three right heart catheterization screenings studies that have recently been published, we defined the presence of pulmonary hypertension for this analysis by a Doppler-echocardiographic measurement of the tricuspid regurgitant jet velocity (TRV) ≥ 3.0 m/s, which has a 67–75% positive predictive value for a mean pulmonary artery pressure ≥ 25 mm Hg by right heart catheterization. This therefore represents a very conservative threshold for a large population screening study. Among subjects with a measurable TRV (n=572), 64 (11.2%) had measurements of ≥ 3.0 m/sec. Among those with measurable NT-proBNP (n=582), 140 (24.1%) had measurements ≥160 pg/mL, a value associated with both pulmonary hypertension and mortality. A total of 39 (7.4%) had both high TRV (≥3.0 m/sec) and high NT-proBNP (≥160 pg/mL). Results: Over a median follow-up time of 29 months, we observed 22 deaths. 50% (N=11) of these patients had a TRV≥ 3.0 m/sec. At 24 months the cumulative survival was 83% for patients with TRV ≥ 3.0 m/sec and 98% for patients with TRV < 3.0 m/sec (p<0.0001). The unadjusted hazard ratios for death were 11.14 (95% CI 4.1–30.1; p<0.0001) for patients with TRV above and below 3.0 m/sec and 4.55 (95% CI 1.8–11.3; p=0.001) for patients with NT-proBNP above and below 160 pg/mL. For patients with both high TRV (≥ 3.0 m/sec) and high NT-proBNP (≥ 160 pg/mL), the unadjusted hazard ratio was 14.86 (95% CI 5.5–39.9; p<0.0001). Overall, an increased risk of death was observed for both age and gender, with males at higher risk relative to females (HR=2.48, 95% CI 1.0–6.1; p=0.05), and patients older than 47 years (HR=2.02, 95% CI 1.1–3.8; p=0.03). Associations with mortality were also observed for chronic transfusions (HR=3.00, 95% CI 1.2–7.8; p=0.02) and a NYHA/WHO class value or III or IV (HR=4.52, 95% CI 1.4–14.3; p=0.01). Other variables associated with mortality in our cohort included a high hemolytic component, aspartate aminotransferase (AST), ferritin, and creatinine. Variables not associated with mortality included current hydroxyurea use, SC disease, self-reported history of painful episodes, and six-minute walk distance. In stepwise multiple proportional hazards regression analysis, the association between TRV and mortality remained significant after adjustment for all other risk factors, including ferritin, AST, creatinine and even NT-proBNP (HR 4.27, 95%CI 1.3–14.1; p=0.04). Conclusions: Using a more conservative cut-off value of TRV ≥ 3.0 m/sec as defining PH in a large screening population of sickle cell disease patients, PH occurs in approximately 10% of unselected screened patients and is associated with the highest unadjusted and adjusted risk for death of any measured variable. Disclosures: Gladwin: Bayer Corp: Consultancy, Research Funding; NIH and NHLBI: Research Funding; Gilead Sciences: Research Funding. Barst:Ventripoint: Stock options Other; Actelion, Eli Lilly, Gilead, Glaxo Smith-Kline (GSK), Medtronics, Bayer, Ikaria, Pfizer, Novartis, VentriPoint: Consultancy, Honoraria. Girgis:NIH/NHLBI: Research Funding, Travel support Other. Rosenzweig:NIH: Research Funding. Badesch:NIH: Research Funding. Lanzkron:NIH: Research Funding.

Despite a wealth of exploratory plasma metabolomics studies in sickle cell disease (SCD), no study to date has evaluate a large and well phenotyped cohort to compare the primary erythrocyte metabolome of hemoglobin SS, SC and transfused AA red blood cells (RBCs) in vivo. The current study evaluates the RBC metabolome of 587 subjects with sickle cell sickle cell disease (SCD) from the WALK PHaSST clinical cohort. The set includes hemoglobin SS, hemoglobin SC SCD patients, with variable levels of HbA related to RBC transfusion events, and HbF related to hydroxyurea therapy. Here we explore the modulating effects of genotype, age, sex, severity of hemolysis, and hydroxyurea and transfusion therapy on sickle RBC metabolism. Data were collated in an online portal and show that the Hb SS genotype is associated with significant alterations of RBC acylcarnitines, pyruvate, sphingosine 1-phosphate, creatinine, kynurenine and urate metabolism. Surprisingly, the RBC metabolism of SC RBCs is dramatically different from SS, with all glycolytic intermediates significantly elevated in SS RBCs, with the exception of pyruvate. This result suggests a metabolic blockade at the ATP-generating phosphoenolpyruvate to pyruvate step of glycolysis, which is catalyzed by redox-sensitive pyruvate kinase. Increasing in vivo concentrations of HbA improved glycolytic flux and normalized the HbS erythrocyte metabolome. An unexpectedly limited metabolic effect of hydroxyurea and HbF was observed, possibly related to the modest induction of HbF in this cohort. The metabolic signature of HbS RBCs correlated with the degree of steady state hemolytic anemia, cardiovascular and renal dysfunction and mortality.

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903 Abstract Background: Deficiency of NADH-cytochrome b5 reductase (cytb5r, EC 1.6.2.2) is responsible for congenital methemoglobinemia. This enzyme exists in soluble and membrane-bound forms. The soluble erythrocytic cytb5r isoenzyme is involved in cytochrome b5 reduction and in erythrocyte methemoglobin reduction; the membrane-bound microsomal enzyme participates in a fatty acid desaturation complex and in drug metabolism. The cytb5r isoforms are the product of a single gene locus, DIA1 (or CYB5R3), on chromosome 22. More then 40 mutations which cause methemoglobinemia have been reported to date; the majority are missense mutations and are associated with mild type I methemoglobinemia. The CYBR5 T116S mutation is the most common genetic polymorphism among African Americans known (gene frequency as high as 20%) and it has not yet been detected in other ethnic and racial groups. This polymorphism is not associated with methemoglobinemia and its functional significance is not yet known. We studied the relationship of CYBR5 T116S with the degree of hemolysis and the tricuspid regurgitation velocity (which correlates with systolic pulmonary artery pressure) in patients with sickle cell disease. Methods: Two hundred sixty one children and adolescents with hemoglobin SS were recruited at three tertiary medical centers and studied at steady state. Patients with other sickle genotypes were excluded from this analysis of CYBR5 T116S. Principal component analysis was used to develop a hemolytic component from reticulocyte count and concentrations of lactate dehydrogenase, aspartate aminotransferase and bilirubin. PCR was used to determine the presence of the CYBR5 T116S mutation. Multivariate models were employed to determine the independent effects of this genotype on degree of hemolysis and tricuspid regurgitation velocity. Results: Ninety-eight of the patients (38%) were CYBR5 T116S heterozygotes and 26 (10%) were homozygotes, consistent with Hardy-Weinberg equilibrium. Both heterozygosity (beta = -0.4) and homozygosity (beta = -0.5) were associated with reduction in the hemolytic component (N = 261; P for trend = 0.002) (Figure 1). This relationship persisted after adjusting for α-thalassemia, hemoglobin F percent and hydroxyurea treatment in a subset of 113 patients with all of this information available (P for trend = 0.037) and it also persisted in a subset of 87 patients with no α-globin gene deletion who were not being treated with hydroxyurea (P for trend = 0.029). In none of these analyses did G6PD-202/-376 have an effect on hemolysis. Both heterozygosity (beta = -0.04) and homozygosity (beta = -0.14) for the CYBR5 T116S mutation were also associated with lower tricuspid regurgitation velocity (P for trend = 0.024). Conclusions: CYBR5 T116S is a common polymorphism among patients with sickle cell disease that appears to be associated with less hemolysis and lower tricuspid regurgitation velocity. We speculate that this polymorphism may be related to a previously reported subpopulation of African Americans with increased cytochrome b5 reductase activity, and that increased anti-oxidant activity may explain the polymorphism's hemolysis-reducing effect. Functional studies to investigate this possibility are planned. Disclosures: No relevant conflicts of interest to declare.